JP2000314620A - Camera for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a camera for vehicle in which the recognition accuracy of an object can be enhanced by eliminating unnecessary background image and detecting the object accurately. SOLUTION: The camera for vehicle fixed to the side part of a vehicle 101 in the vicinity of a back mirror is set with a short imaging pickup distance in the sideward image pickup direction close to the side part of the vehicle 101, as shown by an image pickup range 105 marked with a thick dot line, and thereby it can detect a two-wheeled vehicle 109 accurately without being influenced by the background image, or the like. A long imaging pickup distance is set in the rear sideward image pickup direction substantially parallel with the side part of the vehicle 101 and thereby a two-wheeled vehicle 108 in the rear can be detected accurately. More specifically, an image pickup range comprising an imaging pickup distance and an imaging pickup angle is set differently depending on the image pickup direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicular camera used for detecting a situation around a vehicle.
The present invention relates to a vehicular camera having a visual field whose imaging range varies depending on an imaging direction.

[0002]

2. Description of the Related Art Conventionally, an image of the left side of an own vehicle is taken using a vehicle camera, and when the own vehicle turns left, in order to prevent a two-wheeled vehicle running on the left side of the own vehicle from being involved, the own vehicle is turned left. When the relative distance between the motorcycle and the two-wheeled vehicle determined from the captured image is within a predetermined distance when the device is operated, a technique for issuing an alarm is known.

In such a case, the two-wheeled vehicle traveling on the left side of the own vehicle can reliably detect the two-wheeled vehicle with the vehicle camera even when the two-wheeled vehicle is far from the own vehicle or very close to the own vehicle. For this purpose, it is necessary to increase the imaging range of the vehicle camera, and the imaging range is set to be wide-angle and far.

[0004]

However, in the conventional vehicle camera, since the imaging range is detected at a wide angle and far away, for example, a building existing on the side of the sidewalk is also imaged. Discriminating a motorcycle approaching the vehicle from a large amount of background images takes a very long time, and in order to shorten the time, a high-performance computing device is required, which results in high cost. turn into.

[0005] The present invention has been made in view of the above,
An object of the present invention is to provide a vehicular camera capable of accurately determining a subject to be detected without capturing an unnecessary background image.

[0006]

According to a first aspect of the present invention, there is provided a vehicle camera having a sensor array including a plurality of light receiving sensors and an image forming optical system. The gist of the present invention is that the image capturing range of each of the plurality of light receiving sensors is configured to be different depending on the location of the light receiving sensor in the sensor array.

The present invention according to claim 2 is based on claim 1.
In the described invention, the gist is that each of the plurality of light receiving sensors is configured to have a different sensitivity depending on a location in the sensor array.

[0008] Further, the present invention according to claim 3 provides the invention according to claim 2.
In the present invention described above, each of the plurality of light receiving sensors is constituted by a thermal infrared sensor that converts incident light energy into heat and detects a temperature of a physical property that is changed by the converted heat. The gist is that the sensor is configured so that the thermal resistance of the heat-sensitive part whose physical properties change depending on the temperature and the part other than the heat-sensitive part is different depending on the location of the sensor in the sensor array including the thermal infrared sensor. I do.

According to a fourth aspect of the present invention, in the third aspect of the present invention, the thermal infrared sensor has a thermal isolation structure in which a heat-sensitive portion and a portion other than the heat-sensitive portion are connected by a beam. The gist is that the beams are configured so that the thermal resistance of the beams differs depending on the location of the sensors in the sensor array.

The present invention according to claim 5 provides the present invention as claimed in claim 2.
In the present invention described above, the gist is that each of the plurality of light receiving sensors is configured such that the absorption efficiency with respect to the incident light intensity is different depending on the location in the sensor array.

Further, the present invention according to claim 6 provides the invention according to claim 5.
In the present invention described above, the gist is that each of the plurality of light receiving sensors is configured such that light absorption efficiency in a light receiving region is different depending on a location in a sensor array.

According to a seventh aspect of the present invention, in the fifth aspect of the present invention, each of the plurality of light receiving sensors has a transmittance of a transmission film disposed so as to cover a light receiving area within the sensor array. The gist of the present invention is that it is configured differently depending on the existence site in.

[0013] The present invention described in claim 8 is the first invention.
In the present invention described above, the gist is that each of the plurality of light receiving sensors is configured such that internal noise differs depending on a location in a sensor array.

Further, the present invention described in claim 9 provides the present invention in claim 8.
In the present invention described above, each of the plurality of light receiving sensors has a resistor connected in series to an output, and the resistance is configured to be different depending on a location in the sensor array.

According to a tenth aspect of the present invention, in the first aspect of the present invention, each of the plurality of light receiving sensors has an occupied area or an occupied area of a light detection area existing in the light receiving sensor. The gist is that it is configured to be different depending on the existence site in the inside.

Further, according to the present invention as set forth in claim 11, in the present invention as set forth in claim 1, each of the plurality of light-receiving sensors or the imaging optical system has an extension amount which varies depending on the location of the sensor in the sensor array. The gist of the present invention is as follows.

According to a twelfth aspect of the present invention, in the invention of the eleventh aspect, each of the plurality of light receiving sensors comprises:
The gist is that a light receiving sensor or a minute displacement unit connected to a light receiving area of the light receiving sensor is provided, and the minute displacement unit is configured so that an amount of extension is different depending on an existing portion in the sensor array.

According to a thirteenth aspect of the present invention, in the twelfth aspect of the present invention, the minute displacement means is configured to be able to vary a feeding amount by an input signal applied from the outside. Is the gist.

[0019]

According to the first aspect of the present invention, the image pickup range of each of the plurality of light receiving sensors constituting the sensor array is different depending on the location of the light receiving sensor. By changing the detection distance, unnecessary background images are not captured. As a result, for example, another vehicle such as a two-wheeled vehicle approaching the vehicle side or another vehicle such as a two-wheeled vehicle approaching from a remote position on the rear side of the vehicle can be properly determined as a subject to be detected. Can be.

According to the second aspect of the present invention, since each of the light receiving sensors is configured to have a different sensitivity depending on the location in the sensor array, the sensitivity is changed for each detection direction of each light receiving sensor. Thus, the detection distance can be changed, and the subject to be detected can be accurately determined without capturing an unnecessary background image.

Further, according to the present invention, each of the light receiving sensors is constituted by a thermal infrared sensor, and the thermal resistance between the heat sensitive portion and the other portions of the thermal infrared sensor is determined by the presence of the sensor. Since it is configured differently for each part, the detection distance can be changed by changing the thermal resistance for each detection direction of each light receiving sensor, and the subject to be detected can be accurately detected without taking unnecessary background images. Can be determined.

According to the fourth aspect of the present invention, the thermal infrared sensor is configured such that the heat-sensitive portion and the other portion are connected by a beam, and the beam has a different thermal resistance depending on the location of the sensor. Therefore, the detection distance can be changed by changing the structure of the beam in each detection direction of each light receiving sensor, and the subject to be detected can be accurately determined without capturing unnecessary background images.

According to the fifth aspect of the present invention, since each of the light receiving sensors is configured such that the absorption efficiency with respect to the incident light intensity is different depending on the existing position in the sensor array, the detection direction of each light receiving sensor. The detection distance can be changed by changing the absorption efficiency every time, and the subject to be detected can be accurately determined without capturing an unnecessary background image.

Further, according to the present invention, since each of the light receiving sensors is configured such that the light absorption efficiency in the light receiving area differs depending on the existing portion in the sensor array, the detection of each light receiving sensor is performed. The detection distance can be changed by changing the light absorption efficiency for each direction, and the object to be detected can be accurately determined without capturing unnecessary background images.

According to the seventh aspect of the present invention, each of the plurality of light receiving sensors is configured such that the transmittance of the permeable film covering the light receiving region differs depending on the location in the sensor array. The detection distance can be changed by changing the transmittance of the permeable film for each detection direction, and the subject to be detected can be accurately determined without capturing unnecessary background images.

According to the eighth aspect of the present invention, each of the light receiving sensors is configured such that the internal noise is different depending on the location in the sensor array. Can be changed to change the detection distance, and the subject to be detected can be accurately determined without capturing unnecessary background images.

According to the ninth aspect of the present invention, each of the light receiving sensors is configured such that the resistance connected in series to the output is different depending on the location in the sensor array. The detection distance can be changed by changing the output series resistance for each detection direction, and the object to be detected can be accurately determined without capturing unnecessary background images.

According to the present invention described in claim 10,
Each of the light receiving sensors is configured such that the occupied area of the light detection area is different depending on the existence part in the sensor array. Therefore, it is necessary to change the detection distance by changing the occupation area of the light detection area for each detection direction of each light receiving sensor. Thus, the subject to be detected can be accurately determined without capturing an unnecessary background image.

Further, according to the present invention described in claim 11,
Since each of the light receiving sensors or the imaging optical system is configured such that the extension amount differs depending on the location of the sensor in the sensor array, it is possible to change the detection amount by changing the extension amount for each detection direction of each light receiving sensor. The object to be detected can be accurately determined without capturing unnecessary background images.

According to the twelfth aspect of the present invention, each of the light receiving sensors is configured such that the amount of extension by the minute displacement means is different depending on the existing portion in the sensor array. The detection distance can be changed by changing the extension amount by the minute displacement means, and the subject to be detected can be accurately determined without capturing an unnecessary background image.

According to the thirteenth aspect of the present invention,
Since the minute displacement means can vary the extension amount by an external input signal, the imaging relationship can be varied for each light receiving sensor by the external input signal, and the detection range can be instantaneously changed according to the state of the vehicle.

[0032]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) FIG. 1 is an explanatory diagram showing an imaging range of a vehicle camera according to a first embodiment of the present invention.

The vehicle camera according to the present embodiment having an imaging range as shown in FIG. 1 can be applied to, for example, a vehicle entanglement prevention device, so that the vehicle can travel from a rear position that is far away from the side of the host vehicle. In addition to being able to discriminate a two-wheeled vehicle or the like, it is also possible to accurately discriminate a two-wheeled vehicle or the like close to a side portion of the own vehicle, and it is possible to properly prevent the vehicle from being involved.

In FIG. 1, a motorcycle 109 is running near the left side of the host vehicle 101 in a host vehicle traveling lane 102 where the host vehicle 101 is running.
Another two-wheeled vehicle 108 is also running at a position far away from 01. A pedestrian 107 is walking on the sidewalk 103, and a building 104 is built further on the side of the sidewalk 103. Further, another vehicle 110 is running parallel to the right side of the host vehicle 101 with a slight delay.

In such a situation, the vehicular camera according to the present embodiment has a sensor array composed of a plurality of light receiving sensors and an imaging optical system for guiding an image from a subject to enter the sensor array. It is attached near the rear-view mirror on the left side of the vehicle 101, and has an imaging range indicated by a thick dotted line 105 starting from the vicinity of the rear-view mirror. The imaging range 105 is set so as to be able to image only a short distance with respect to the left side of the host vehicle 101, so that the motorcycle 109 traveling close to the left side can be accurately determined. And own vehicle 1
01 is set so that it can be imaged at a long distance from the rear side, so that the motorcycle 108 existing on the rear side far away from the host vehicle 101 can also be accurately identified.

In contrast to the above-described imaging range 105 of the present embodiment, a conventional camera device or the like has an imaging range 106 that can be detected at a wide angle and a distant position as indicated by a dashed line in FIG. For this reason, in addition to the two-wheeled vehicle, image information of an unnecessary background such as the building 104 is also captured, and it has been difficult to determine the two-wheeled vehicles 108 and 109 which are the objects to be determined. That is, since the vehicle camera of the present embodiment has the imaging range 105 indicated by the thick dotted line,
The image information of the motorcycles 108 and 109, which are the objects to be imaged, is taken in, and the image information of the unnecessary objects such as the building 104 or the like is not taken in.

More specifically, the imaging range 105 of the vehicle camera according to the present embodiment has the same wide angle as the conventional imaging range 106, but has the same direction as that of the host vehicle 101 for discriminating the motorcycle 109. The imaging distance is set short for the imaging direction on the side closer to the side, so that the motorcycle 109 can be accurately determined without being affected by the background image and the like, and can be almost parallel to the host vehicle 101. The image pickup distance is set long in the image pickup direction on the rear side toward the rear part, so that the rear motorcycle 108 can be accurately identified. That is, the imaging range including the imaging distance and the imaging angle is set to be different depending on the imaging direction.

The sensor array of the vehicular camera constituting such an imaging range 105 has a short imaging distance over a wide angle from a side substantially perpendicular to the side of the vehicle 101 to a rear side substantially parallel to the side. A large number of light receiving sensors from a light receiving sensor to a long light receiving sensor are arranged continuously.

Next, a vehicle camera having such an imaging range 105 will be described in detail.

In general, a signal-to-noise ratio (hereinafter abbreviated as S / N) of a vehicle camera with respect to a distance to an object, that is, a rate of change in sensitivity of the vehicle camera with respect to the distance, is determined by an attenuation caused by a transmission line such as the atmosphere. If ignored, the relationship shown in FIG. 2 is established. When the distance to the subject is small until the critical distance x is reached (region A), the S / N is constant without depending on the distance. (Area B) also decreases with the square of the distance. This is because when the size of the subject becomes smaller than the spatial resolution of the camera, the energy incident on the light receiving sensor decreases. In general, since the spatial resolution of the lens of the optical system of the vehicle camera is superior to the resolution of the light receiving sensor, the resolution of the lens does not limit the resolution of the camera. Is determined by

In the vehicle camera according to the present embodiment, the directional dependency of the imaging distance is realized by changing the critical distance x according to the imaging direction and changing the S / N according to the imaging direction and the imaging distance. are doing.

That is, in a sensor array composed of a plurality of light receiving sensors, a light receiving sensor that wants to image a long distance is configured to increase the critical distance x, and a light receiving sensor that wants to image only the vicinity has a small critical distance x. Constitute. Specifically, there are a method of changing the S / N according to the imaging direction, a method of changing the spatial resolution according to the imaging direction, a method of changing the amount of extension according to the imaging direction, and the like.

First, as a vehicle camera according to the first embodiment of the present invention, the S / N of a plurality of light receiving sensors constituting a sensor array is changed according to the imaging direction of each light receiving sensor. The S / N of each of the plurality of light receiving sensors is configured such that the S / N of the light receiving sensor that wants to image a long distance is set large, and the S / N of the light receiving sensor that wants to image only a short distance is set small. is there.

More specifically, as shown in FIG. 3, a light-receiving sensor that wants to image a long distance, that is, a light-receiving sensor having a long imaging distance, has a large S / N ratio, and a light-receiving sensor that wants to image only a short distance, that is, an imaging sensor. A light receiving sensor having a short distance has a small S / N. Specifically, for example, by increasing the S / N of a light receiving sensor that detects the rear side of the vehicle or a pixel that constitutes the light receiving sensor that wants to image far away,
The S / N of the light receiving sensor that captures an image of the side near the vehicle that is not affected by the background or the like and the pixels that constitute the light receiving sensor are set to be small. Note that this configuration is advantageous when the incident energy density from the background is smaller than that of the subject.

Since S / N is the ratio of the signal S to the noise N, the configuration for changing the S / N of the light receiving sensor as in the present embodiment includes the configuration for changing the signal S and the noise N There is a configuration to make it.

A configuration for changing the signal S will be described. To change the signal S, it is sufficient to change the sensitivity of the light receiving sensor. Since the sensitivity indicates the efficiency of converting incident light energy to voltage, the conversion efficiency of converting this incident light energy to voltage is detected. What is necessary is just to change by the pixel which comprises a sensor or a light receiving sensor.

Each of the plurality of light receiving sensors constituting the sensor array may be constituted by one pixel, or may be constituted by a plurality of pixels.
Accordingly, the present invention is not limited to this. Therefore, in the following description, the light receiving sensor or the pixel forming the light receiving sensor will be simply described as a light receiving sensor in the following description.

As a configuration for changing the conversion efficiency, in the first embodiment, when the light receiving sensor is, for example, a photosensor, a phototransistor, a photoconductive element or the like utilizing the internal photoelectric effect, the light absorption efficiency is changed. Is achieved by a configuration that changes Specifically, as shown in FIG. 4, the filter 204 is configured by disposing filters 204 having different light transmittances in front of the sensor array 201 configuring a plurality of light receiving sensors.

That is, the filter 204 disposed in front of the sensor array 201 is thicker on the upper side and thinner on the lower side in FIG. 4, but the light receiving sensor located on the upper side is thicker. Since the light attenuated by the filter 204 is incident, only short-range image information can be obtained without being affected by a distant background image or the like.
In the lower light receiving sensor, the thin filter 2
In 04, light that has not been attenuated is incident, and a distant subject can be detected.

By providing the filter 204 having such a configuration in front of the sensor array 201, the sensor array 2
01 means to obtain an imaging range 205. In FIG. 4, reference numeral 202 denotes an optical axis, and reference numeral 203 denotes an imaging optical system.

Here, the operation and effect of the vehicle camera according to the first embodiment will be described.

Since the detectable range of each of the plurality of light receiving sensors constituting the sensor array is different depending on the location of the light receiving sensor, an unnecessary background image can be obtained by changing the imaging distance for each imaging direction. There is no imaging. As a result, as shown in FIG. 1, other vehicles such as the motorcycle 109 approaching the vehicle side and other vehicles such as the motorcycle 108 approaching from a remote position on the rear side of the vehicle are detected. It can be accurately determined as a subject to be shot.

If a photosensor, a phototransistor, a photoconductive element, or the like is used as the light receiving sensor, each of the light receiving sensors is configured such that the absorption efficiency with respect to the intensity of the incident light differs depending on the location in the sensor array. The imaging distance can be changed by changing the absorption efficiency for each detection direction of each light receiving sensor, and the subject to be detected can be accurately determined without capturing unnecessary background images.

Further, a photo sensor as a light receiving sensor,
If a phototransistor, a photoconductive element, or the like is used, each of the light receiving sensors is configured such that the light absorption efficiency in the light receiving area differs depending on the existence site in the sensor array. The imaging distance can be changed by changing the absorption efficiency, and the subject to be detected can be accurately determined without capturing unnecessary background images.

Further, since each of the plurality of light receiving sensors is configured such that the transmittance of the filter 204 covering the light receiving area differs depending on the existing position in the sensor array, the transmission of the filter 204 for each detection direction of each light receiving sensor is performed. The imaging distance can be changed by changing the rate, and the subject to be detected can be accurately determined without capturing unnecessary background images.

(Second Embodiment) As a second embodiment of the present invention, the light receiving sensor utilizes the internal photoelectric effect, and the thickness of the active layer for generating carriers is changed. A method of changing the S / N signal S of the light receiving sensor will be described.

Specifically, as shown in FIG. 5, an active layer 206 is disposed in front of the sensor array 201 in place of the filter 204 shown in FIG. 4, and the thickness of the active layer 206 is changed. It is.

That is, the active layer 206 disposed in front of the sensor array 201 is configured such that the thickness is thinner on the upper side and thicker on the lower side in FIG. Since a thin active layer generates a small amount of carriers, only a subject at a short distance can be imaged.On the other hand, in a light receiving sensor located on the lower side, a large active layer generates a large amount of a carrier, so that a distant subject can be imaged. Can be imaged.

By providing the active layer 206 having such a configuration before the sensor array 201, the sensor array 201 of FIG.

Here, the operation and effect of the vehicle camera according to the second embodiment will be described.

Since each of the light receiving sensors is configured such that the generation of carriers is different depending on the existence site in the sensor array 201 by the active layer 206, the amount of generated carriers is changed for each detection direction of each light receiving sensor, and the imaging distance is changed. Can be changed, and the subject to be detected can be accurately determined without capturing an unnecessary background image.

(Third Embodiment) Next, a third embodiment of the present invention will be described.
As an embodiment of the present invention, in the case where a plurality of light receiving sensors constituting a sensor array are light receiving sensors such as a thermopile or a porometer for converting light energy in an infrared sensor to heat energy, for example, A method of changing the signal S of the S / N by changing the thermal resistance will be described.

First, a thermopile type light receiving sensor will be described with reference to FIGS. 6 (a) and FIG. 6 (b) differ only in the shape of the beam, and that point will be described later, and will be described mainly with reference to FIG. 6 (a).

Reference numeral 208 denotes a low-sensitivity light receiving sensor having a hot junction 13 and a cold junction 14 on a diaphragm formed on a semiconductor substrate through a cavity. This hot junction 13
And the cold junction 14 are alternately connected by the p-type polysilicon 6 and the n-type polysilicon 7 formed on the beam 16 to detect heat (light) incident on the heat absorbing film 4. is there. At this time, the light (light) incident on the heat absorbing film 4 is transmitted to the substrate by the beam 16. Therefore, if the thickness of the beam 16 is large, the thermal resistance increases accordingly,
It is difficult to transmit the heat incident on the heat absorbing film 4 to the substrate side, that is, the detected sensitivity is low. Therefore, when the thickness of the beam 20 is smaller than the thickness of the beam 16 shown in FIG. 6A as shown in FIG. 6B, the thermal resistance is reduced, so that heat is easily transmitted, and the detection sensitivity is reduced. Get better.

By forming the beams 16 and 20 to be narrow or wide, the hot junction 13 and the cold junction 14 are formed.
And the thermal resistance between them can be varied, thereby changing the detection sensitivity of the light receiving sensor. By combining a plurality of light receiving sensors having different detection sensitivities in accordance with a desired imaging direction in this manner, a sensor array having different imaging distances depending on the imaging direction, such as the imaging range 105 shown in FIG. 1, can be configured. .

FIG. 7 is a diagram showing a sensor array 201 formed by combining a plurality of light receiving sensors having different imaging distances as described with reference to FIGS. 6A and 6B, and an imaging range 205 thereof. In FIG. 7, the sensor array 201 includes a plurality of light receiving sensors 207a, 207b, 208a, and 208b. The light receiving sensor 207a has the highest sensitivity, has a long imaging distance, and the next light receiving sensor 207b.
Has the next highest sensitivity and the next longest imaging distance, and the imaging distance gradually decreases, and the light receiving sensor 208b has the lowest sensitivity and the shortest imaging distance.

Here, the operation and effects of the vehicle camera according to the third embodiment will be described.

Since each of the light receiving sensors has a different sensitivity depending on the location in the sensor array 201, the imaging distance can be changed by changing the sensitivity for each detection direction of each light receiving sensor, and unnecessary background can be changed. The subject to be detected can be accurately determined without capturing an image.

Each of the light receiving sensors is constituted by a thermopile type infrared sensor, and the heat resistance of the thermosensitive part of the thermopile type infrared sensor is different from that of the other parts depending on the location of the sensor. The imaging distance can be changed by changing the thermal resistance for each detection direction of each light receiving sensor, and the subject to be detected can be accurately determined without capturing unnecessary background images.

Further, in the thermopile type infrared sensor, the heat-sensitive portion and the other portions are connected by beams 16 and 20, and the beams are configured so that the thermal resistance of the beams differs depending on the location of the sensor. The imaging distance can be changed by changing the structure of the beam in each detection direction of the sensor, and the subject to be detected can be accurately determined without capturing unnecessary background images.

(Fourth Embodiment) Next, a fourth embodiment of the present invention will be described.
As an embodiment of the present invention, a configuration for changing noise N in S / N will be described with reference to FIG.

FIG. 8 shows a sensor array 201 composed of shunt resistors 214a, 214b, 214c and 214d connected to the outputs of a plurality of light receiving sensors, and its imaging range 20.
5 is shown. The resistance value of the shunt resistor 214a is reduced in order such that the resistance value of the shunt resistor 214a is the largest and then the resistance value of the shunt resistor 214b is the largest.
The shunt resistor 214 is configured to have a different resistance value depending on the light receiving sensor such that the resistance value of d is the smallest.

In such a configuration, the thermal noise of the shunt resistor 214a having the largest resistance value is the largest, so that
S of the light receiving sensor to which the shunt resistor 214a is connected
/ N is the smallest, and the imaging distance is short. Further, since the thermal noise of the shunt resistor 214d having the smallest resistance value is the smallest, the S / N of the light receiving sensor is the largest, and the imaging range 20 of the sensor array configured in this manner.
5 is as shown in FIG. In FIG. 8, the shunt resistors 214a to 214d are shown by circuit symbols of variable resistors, but may be fixed resistors.

Here, the operation and effects of the vehicle camera according to the fourth embodiment will be described.

Since each of the light receiving sensors is configured so that the thermal noise differs depending on the location in the sensor array 201, the imaging distance can be changed by changing the thermal noise for each detection direction of each light receiving sensor. The subject to be detected can be accurately determined without capturing an unnecessary background image.

Further, since each of the light receiving sensors is configured such that the shunt resistance connected in series to the output differs depending on the location in the sensor array 201, the output series resistance is changed for each detection direction of each light receiving sensor. To change the imaging distance, and without capturing unnecessary background images,
The subject to be detected can be determined accurately.

(Fifth Embodiment) The fifth embodiment of the present invention
As an embodiment of the present invention, a configuration in which the temperature of the light receiving sensor is increased in order to change the noise N in the S / N will be described.

A heating element is arranged near the light receiving sensors arranged in an array. At this time, for example, when the sensor array is configured by three light receiving sensors, the heating elements are arranged so that heat applied to each light receiving sensor is different.

The heating element is formed by, for example, passing a current through a resistor formed of a semiconductor. Therefore, the light receiving sensor closest to the heating element receives the heat from the heating element most, so that thermal noise increases. Conversely, the light-receiving sensor farthest from the heating element is less likely to receive heat from the heating element, so that thermal noise is reduced.
Therefore, the imaging distance of the light receiving sensor closest to the heating element is short, and the imaging distance of the light receiving sensor furthest to the heating element is long.

Here, the operation and effects of the vehicle camera according to the fifth embodiment will be described.

Since each of the light receiving sensors is configured such that the temperature of the light receiving region heated by the heating element differs depending on the location, the image pickup distance is changed by changing the temperature of the light receiving region for each detection direction of each light receiving sensor. The object to be detected can be accurately determined without capturing unnecessary background images.

(Sixth Embodiment) Next, a sixth embodiment of the present invention will be described.
As an embodiment, a configuration for changing the spatial resolution will be described with reference to FIG. This is because, by changing the pixel size or aperture ratio of the light receiving sensor,
That is, the critical distance x is changed for each pixel constituting the light receiving sensor.

The image formed by the light receiving sensor having a large pixel size is large on the object surface. Therefore, at a short distance, the resolution of the light receiving sensor is equivalent to the size of the subject, so that the critical distance x becomes shorter as the critical distance x2 in FIG. 9 as the critical distance x1.

That is, by configuring the sensor array so that the pixel size of each light receiving sensor is different, the imaging distance of the light receiving sensor having a small pixel size is set large, and the imaging distance of the light receiving sensor having a large pixel size is set small. Will be done.

Further, a net light receiving area (corresponding to a pn junction area or an opening in a light receiving sensor utilizing the internal photoelectric effect,
The ratio of the thermal infrared sensor to the sensor size (corresponding to the absorption film) is called the aperture ratio. The critical distance x is long for a light receiving sensor having a small aperture ratio for the same reason as the pixel size dependency. Therefore, in a sensor array in which light receiving sensors of the same pixel size are arranged two-dimensionally, the imaging distance is changed by changing the aperture ratio. Can be changed. That is, by configuring the sensor array so that the aperture ratio of each light receiving sensor is different, the imaging distance of the light receiving sensor having a small aperture ratio is set large, and the imaging distance of the light receiving sensor having a large aperture ratio is set small.

Here, the operation and effects of the vehicle camera according to the sixth embodiment will be described.

Since each of the light receiving sensors is configured such that the opening area occupied as the light detecting area differs depending on the location in the sensor array, the opening occupied as the light detecting area for each detection direction of each light receiving sensor. The imaging distance can be changed by changing the area, and the subject to be detected can be accurately determined without capturing unnecessary background images.

(Seventh Embodiment) Next, a seventh embodiment of the present invention will be described.
As an embodiment of the present invention, the focus is shifted by changing the feeding amount, and the S / N ratio is changed by changing the degree of focusing for each light receiving sensor.
Will be described with reference to FIGS. 10 and 11. FIG.

In order to form an image of a subject at a finite distance on the light receiving sensor, it is necessary to satisfy a relationship expressed by a Newton imaging formula or the like, as is well known. In the case where there is no blur, that is, a so-called blurred state, that is, a state where the incident energy is diffused in a wide range, and the energy density incident on a predetermined pixel becomes low, so that S / S
N decreases.

Therefore, by utilizing such a state, it is possible to change the degree of focusing for each pixel constituting the light receiving sensor, thereby changing the imaging distance.

In FIG. 10, when the subject 224 forms an image 225 by the imaging optical system 203, an imaging relationship as shown in FIG. 10 is obtained. Reference numeral 220 denotes a front focus, and 221 denotes a rear focus.

The light emitted from the tip of the subject 224 is
At a distance that satisfies the Newton's imaging formula, if aberrations are ignored, an image is focused on one point and a blur-free image is obtained, and light with a very high incident density enters the light receiving sensor.

However, if the optical axis 202 is shifted back and forth, the image-forming relationship is not satisfied.
It will spread over a certain area. If it is shifted in the positive direction of the optical axis, the state becomes the so-called front pin 222, and if it is shifted in the negative direction, it becomes the state of the rear pin 223.

As described above, in order to change the degree of focusing for each pixel constituting the light receiving sensor, the position of the pixel in the optical axis direction is changed. Specifically, FIG.
As shown in (2), the sensor array 201 including a plurality of light receiving sensors is inclined from a direction perpendicular to the optical axis 202. In the sensor array 201 tilted in this way, FIG.
In FIG. 1, the lower light receiving sensor is located at a position 209 that satisfies the Newton imaging formula, so that it is in focus and has a large imaging distance, but the upper light receiving sensor is extended forward by the distance 211 and the front focus position Since it is located at 210, it is not in focus and the imaging distance is short. As a result, an imaging range as indicated by 205 in FIG. 11 is formed in the entire sensor array.

Here, the operation and effect of the vehicle camera according to the seventh embodiment will be described.

Each of the light receiving sensors or the imaging optical system is configured so that the amount of extension differs depending on the location of the sensor in the sensor array 201. Therefore, the amount of extension is changed for each detection direction of each light receiving sensor to change the imaging distance. Can be changed, and the subject to be detected can be accurately determined without capturing an unnecessary background image.

(Eighth Embodiment) An eighth embodiment of the present invention will be described.
As an embodiment of the present invention, referring to FIG. 12, a configuration in which a payout amount is changed for each pixel to shift a focus by using a micromachine technology, and a S / N is changed by changing a degree of focusing for each light receiving sensor. explain.

That is, as shown in FIG. 12, a piezo element 213 serving as a minute displacement means is provided on the main surface of the sensor array 201 for each light receiving sensor.
The light receiving sensor 212 is provided via the.

In such a configuration, the piezo element 21
Since 3 expands and contracts by the inverse piezoelectric effect in response to a voltage signal applied from the outside, the extension amount can be changed for each light receiving sensor by this expansion and contraction. Then, the lower light receiving sensor 212 in FIG.
Is substantially in focus, the imaging distance is large, and the upper light receiving sensor extending toward the imaging optical system 203 is not in focus, and the imaging distance is short.

As a result, in the entire sensor array, FIG.
, An imaging range as indicated by 205 is formed.

Here, the operation and effects of the vehicle camera according to the eighth embodiment will be described.

Since each of the light receiving sensors 212 is configured so that the amount of extension by the minute displacement means differs depending on the existing portion in the sensor array 201, the amount of extension is changed by the minute displacement means for each detection direction of each light receiving sensor. The imaging distance can be changed, and the subject to be detected can be accurately determined without capturing unnecessary background images.

Further, since the minute displacement means can vary the feeding amount by an external input signal, the imaging relationship can be varied for each light receiving sensor by the external input signal, and the detection range can be instantaneously changed according to the state of the vehicle. Can be changed.

In FIG. 12, the light receiving sensor 21
Although only two and two piezo elements 213 are shown for simplicity of the drawing, it goes without saying that a plurality of light receiving sensors and piezo elements are provided.

Further, in the above embodiment, the piezo element 213 is used as the minute displacement means for changing the feeding amount for each light receiving sensor. However, the present invention is not limited to the piezo element 213. The used elements and the like can also be used.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an imaging range of a vehicle camera according to a first embodiment of the present invention.

FIG. 2 is a diagram showing the relationship between the distance between a general camera and a subject and the S / N of a light receiving sensor.

FIG. 3 illustrates a distance between a vehicle camera and a subject and an S of a light receiving sensor for explaining a principle according to the first embodiment.
FIG. 6 is a diagram showing a relationship with / N.

FIG. 4 is a diagram illustrating a sensor array including filters having different light transmittances and an imaging range of the sensor array according to the first embodiment.

FIG. 5 is a diagram showing a sensor array having active layers having different thicknesses in a second embodiment of the present invention and an imaging range thereof.

FIG. 6 is a diagram showing a configuration of a thermopile constituting a light receiving sensor according to a third embodiment of the present invention.

7 is a diagram showing a sensor array configured by combining the light receiving sensors made of the thermopile shown in FIG. 6 and an imaging range thereof.

FIG. 8 is a diagram illustrating a sensor array including a light receiving sensor in which a shunt resistor is connected to each output and an imaging range of the sensor array according to the fourth embodiment of the present invention.

FIG. 9 is a diagram for explaining a principle of changing a critical distance x for each pixel constituting a light receiving sensor by changing a pixel size or an aperture ratio of the light receiving sensor in a sixth embodiment of the present invention.

FIG. 10 is a view for explaining the principle of a configuration in which the S / N is changed by changing the amount of extension to shift the focus and changing the degree of focusing for each light receiving sensor in the seventh embodiment of the present invention. FIG.

FIG. 11 is a diagram showing a sensor array which is arranged to be tilted to change the feeding amount in the seventh embodiment shown in FIG. 10 and an imaging range thereof;

FIG. 12 is a diagram showing a sensor array in which a piezo element is provided for each light receiving sensor in order to change a feeding amount in an eighth embodiment of the present invention, and an imaging range thereof.

[Explanation of symbols]

 Reference Signs List 13 hot junction 14 cold junction 16 beam 101 own vehicle 105, 205 imaging range 201 sensor array 204 filter 206 active layer 212 light receiving sensor 213 piezo element 214 shunt resistance

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B60R 21/00 624C 624D 628Z G01V 9/04 P

Claims (13)

[Claims] 1. A vehicular camera having a sensor array including a plurality of light receiving sensors and an imaging optical system, wherein an imageable range of each of the plurality of light receiving sensors is defined by a location of the light receiving sensor in the sensor array. A vehicular camera characterized in that it is configured differently for each vehicle. 2. The vehicle camera according to claim 1, wherein each of the plurality of light receiving sensors is configured to have a different sensitivity depending on a location in a sensor array. 3. Each of the plurality of light-receiving sensors is constituted by a thermal infrared sensor that converts incident light energy into heat and detects a temperature of a physical property that is changed by the converted heat. Wherein the thermal resistance of the heat-sensitive part whose physical properties change with temperature and the heat resistance of the part other than the heat-sensitive part are different depending on the location of the sensor in the sensor array including the thermal infrared sensor. The vehicle camera according to claim 2. 4. The thermal infrared sensor has a thermal isolation structure in which a heat-sensitive portion and a portion other than the heat-sensitive portion are connected by a beam, and the thermal resistance of the beam is a portion where the sensor exists in a sensor array. 4. The vehicular camera according to claim 3, wherein the beams are configured so as to be different from each other. 5. The vehicle camera according to claim 2, wherein each of the plurality of light receiving sensors is configured such that an absorption efficiency with respect to an incident light intensity differs depending on a location in a sensor array. 6. The vehicular camera according to claim 5, wherein each of the plurality of light receiving sensors is configured such that light absorption efficiency in a light receiving area differs depending on a location in a sensor array. 7. Each of the plurality of light-receiving sensors is configured such that the transmittance of a permeable film disposed so as to cover a light-receiving region varies depending on a portion present in a sensor array. The vehicle camera according to claim 5. 8. The vehicular camera according to claim 1, wherein each of the plurality of light receiving sensors is configured such that internal noise varies depending on a location in a sensor array. 9. Each of the plurality of light receiving sensors has a resistor connected in series to an output, and the resistance is configured to be different depending on a location in the sensor array. 8. The vehicle camera according to 8. 10. Each of the plurality of light receiving sensors is configured such that an occupied area or an occupied area of a light detection area existing in the light receiving sensor differs depending on an existing part in a sensor array. Item 4. The vehicle camera according to Item 1. 11. The vehicle according to claim 1, wherein each of the plurality of light-receiving sensors or the imaging optical system is configured such that an amount of extension differs depending on a location of the sensor in a sensor array. camera. 12. Each of the plurality of light-receiving sensors has a light-receiving sensor or a minute displacement means connected to a light-receiving area of the light-receiving sensor, so that an amount of extension by the minute displacement means varies depending on an existing portion in the sensor array. The vehicular camera according to claim 11, wherein: 13. The apparatus according to claim 1, wherein the minute displacement means is configured to be able to change a feeding amount by an input signal applied from the outside.
2. The vehicle camera according to 2.